The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Hybrid electric vehicles (HEVs) and plug-in HEVs use multiple propulsion systems to provide motive power. The propulsion systems may include electric or battery powered systems that receive power from one or more battery packs. A battery pack may include, for example, one or more banks of high-voltage cells (or batteries), such as lithium ion cells. The cells are volumetric building blocks of the battery pack.
The operating temperature of a cell can affect the lifespan and performance (charging and discharging efficiencies) of the cell. Regulating the operating temperature of a cell within a predetermined operating temperature range may maximize lifespan and performance of the cell.
Within a battery pack, however, the operating temperatures of the cells may vary from cell to cell. Temperature variations can arise between the cells of a battery pack for various reasons. For example only, temperature variations can arise due to manufacturing differences between the cells, differences in locations of the cells within the battery pack, thermal path differences of each cell, and other reasons. It can be difficult to maintain each of the cells of a battery pack within the predetermined operating temperature range.